Coagulation Factor XIIIA: biochemical properties underlying physiological function.

Factor XIIIA (FXIIIA) is a transglutaminase that crosslinks intra- and extracellular protein substrates. The oligomeric state of active FXIIIA remains controversial, and the present work commenced with addressing this issue. The results of size exclusion chromatography and analytical ultracentrifugation confirmed a dimeric state for zymogen and, for the first time, indicated a monomeric state for the active FXIIIA in solution. Comparing sedimentation properties of proteolytically and nonproteolytically activated FXIIIA suggested conformational and functional differences between the two forms. Those differences were further assessed in a series of catalytic activity studies. Kinetic analysis revealed affinity for the glutamine substrate was higher for proteolytically activated FXIIIA than for FXIIIA activated by high mM Ca2+. FXIIIA proteolytic activation was investigated in a context of fibrin clotting. The V34X FXIIIA variants were generated using site-directed mutagenesis and recombinantly expressed in Escherichia coli. Those variants were ranked in terms of their activation rates by thrombin L34\u3e\u3eV34\u3eF34\u3e\u3eW34. In a series of SDS-PAGE and clot turbidity assays, the proteolytic activation rates of FXIIIA variants were correlated with the extent of covalent fibrin crosslinking. The V34X FXIIIA variants were administered into murine FXIIIA-deficient plasma. Scanning electron microscopy of the whole plasma clots revealed morphological evidence for incorporation of nonfibrous protein into the clot. The magnitude of this incorporation correlated with the FXIIIA activation rate. Overall, the presented research fills in critical gaps in previously identified FXIIIA biochemical attributes and expands the understanding of FXIIIA physiological function

Evidence for TTAGG telomere repeats and rRNA gene clusters in leafhoppers of the genus Alebra (Hemiptera: Auchenorrhyncha: Cicadellidae)

The leafhopper genus Alebra Fieber, 1872 comprises a complex of morphologically similar species. The chromosome complements (karyotypes) of five Alebra species, i.e. A. albostriella, A. coryli, A. viridis, A. wahlbergi and a new, yet undescribed species, provisionally named Taxon 1, were here investigated, three of these species (A. coryli, A. viridis, and Taxon 1) for the first time. The techniques applied included standard chromosome staining, fluorescence in situ hybridization (FISH) for mapping of 18S rDNA and telomeric repeats (in every species), C-banding, AgNOR-banding and CMA3 /DAPI- staining (in A. viridis). The species have a holokinetic type of chromosomes, as in other hemipterans. Karyotypes of all species are remarkably conserved with 2n = 22 + X(0)/XX (male/female), one large and 10 medium pairs of autosomes and the X chromosome similar in size to larger chromosomes within this group. In every species, FISH identified the “classical” insect telomere repeat of TTAGG and rRNA gene clusters located on the homologues of a medium-sized pair of autosomes, presumably number 5. Thus, speciation in Alebra has apparently not involved significant karyotypic changes. In A. viridis, rDNA sites were both Ag- and CMA3 -positive and were located at an interstitial position. C-banding revealed heterochromatic bands in the X chromosome and also in all but four pairs of autosomes, the bands were located at one telomere of a chromosome. C-bands were positive for CMA3 and negative for DAPI, suggesting that C-heterochromatin is mainly enriched in GC-pairs.info:eu-repo/semantics/publishedVersio

Clinical picture, diagnosis and treatment of patiets suffering from inadequate operations and recurrences of struma maligna

Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Viral and Host Factors Regulating HIV-1 Envelope Protein Trafficking and Particle Incorporation

The HIV-1 envelope glycoprotein (Env) is an essential structural component of the virus, serving as the receptor-binding protein and principal neutralizing determinant. Env trimers are incorporated into developing particles at the plasma membrane of infected cells. Incorporation of HIV-1 Env into particles in T cells and macrophages is regulated by the long Env cytoplasmic tail (CT) and the matrix region of Gag. The CT incorporates motifs that interact with cellular factors involved in endosomal trafficking. Env follows an unusual pathway to arrive at the site of particle assembly, first traversing the secretory pathway to the plasma membrane (PM), then undergoing endocytosis, followed by directed sorting to the site of particle assembly on the PM. Many aspects of Env trafficking remain to be defined, including the sequential events that occur following endocytosis, leading to productive recycling and particle incorporation. This review focuses on the host factors and pathways involved in Env trafficking, and discusses leading models of Env incorporation into particles

FISH-based karyotyping of Pelmatohydra oligactis (Pallas, 1766), Hydra oxycnida Schulze, 1914, and H. magnipapillata It\uf4, 1947 (Cnidaria, Hydrozoa)

Volume: 12Start Page: 539End Page: 54

Karyotypes, male meiosis and comparative FISH mapping of 18S ribosomal DNA and telomeric (TTAGG)n repeat in eight species of true bugs (Hemiptera, Heteroptera)

Volume: 5Start Page: 355End Page: 37

Ribosomal DNA clusters and telomeric (TTAGG)n repeats in blue butterflies (Lepidoptera, Lycaenidae) with low and high chromosome numbers

Volume: 9Start Page: 161End Page: 17

Karyotype diversity in the genus Nysius Dallas, 1852 (Hemiptera, Heteroptera, Lygaeidae) is much greater than you might think

We studied the karyotype and chromosomal distribution of 18S rDNA clustered in nucleolar organizer regions (NORs) in Nysius graminicola (Kolenati, 1845), belonging to the subfamily Orsillinae (Lygaeidae). It is shown that this species has a karyotype with 2n = 22(18+mm+XY), previously known in only one of 24 studied species of the genus Nysius Dallas, 1852, characterized by a similar karyotype, 2n = 14(12+mm+XY). In N. graminicola, 18S loci are located on sex chromosomes, which is a previously unknown trait for this genus. Our results in a compilation with previous data revealed dynamic evolution of rDNA distribution in Nysius. It is concluded that molecular chromosomal markers detected by FISH contribute to a better understanding of the structure and evolution of the taxonomically complex genus Nysius

Comparative FISH mapping of ribosomal DNA clusters and TTAGG telomeric sequences to holokinetic chromosomes of eight species of the insect order Psocoptera

Repetitive DNAs are the main components of eukaryotic genome. We mapped the 18S rDNA and TTAGG telomeric probe sequences by FISH to meiotic chromosomes of eight species of the order Psocoptera considered a basal taxon of Paraneoptera: Valenzuela burmeisteri (Brauer, 1876), Stenopsocus lachlani Kolbe, 1960, Graphopsocus cruciatus (Linnaeus, 1768), Peripsocus phaeopterus (Stephens, 1836), Philotarsus picicornis (Fabricius, 1793), Amphigerontia bifasciata (Latreille, 1799), Psococerastis gibbosa (Sulzer, 1766), and Metylophorus nebulosus (Stephens, 1836). These species belong to five distantly related families of the largest psocid suborder Psocomorpha: Caeciliusidae, Stenopsocidae, Peripsocidae, Philotarsidae, and Psocidae. We show that all the examined species share a similar location of 18S rDNA on a medium-sized pair of autosomes. This is the first study of rDNA clusters in the order Psocoptera using FISH. We also demonstrate that these species have the classical insect (TTAGG)n telomere organization. Our results provide a foundation for further cytogenetic characterization and chromosome evolution studies in Psocoptera